Helmet seal



May 26, 1959 K. E. PENROD ET AL HELMET SEAL Filed 001;. 12, 1949 r ll INVENTORY f, Pf vkaa KEN/V5777 BTTOE VEYS United States Patent HELMET SEAL Kenneth E. Penrod, Needham, and David M. Clark, Worcester, Mass., assignors to the United States of America as represented by the Secretary of the Air Force Application October 12, 1949, Serial No. 121,012

8 Claims. (Cl. 128-143) This invention relates to pressurized helmets and more especially to a seal to prevent leakage of pressure at the juncture between the helmet and the body of the wearer. It is particularly adaptable for use in connection with a partial pressure suit.

One of the greatest difliculties in the development of devices of this character, such as oxygen masks, helmets and other respiratory devices is the difficulty of providing a satisfactory pressure seal to the skin. Current practice generally is to use an inflatable bladder to effect a seal around the face and ears, the pressure maintained in the bladder being substantially higher than the pressure which maintains in the area which is to be sealed which of course increases the complexity of the supply devices.

The principal objects of the herein disclosed invention are to provide a seal which requires a less critical fit of the helmet with the wearers body, requires no greater pressure within the helmet to maintain the seal than the respiratory pressure required by the wearer, and is quite simple in construction and in its application.

The device which we have developed to attain these objects consists essentially of a transparent plastic helmet open at the bottom, the opening of the helmet at the bottom edge being large enough to admit the wearers head, the edge of the opening being shaped to substantially conform to the wearers shoulders, with an annular flap surrounding the inner periphery of the open end of the helmet which is pressed down on the wearers shoulders by the excess in the respiratory pressure over that of the ambient air.

Referring to the drawing, wherein Fig. 1 shows a front elevation of our improved helmet in place on a wearer, and Fig. 2 a modification of the device of Fig. 1, and wherein like reference characters refer to like parts,

A dome-like helmet of plexiglass or similar transparent material is shaped to a contour enough larger than the average human head 12 to leave a space 14 which is to be pressurized. The edge 16 of the dome 10 is made to follow the average shoulder outline as nearly as possible but is widened and made less sharp by an annular rib 18 of U-shaped cross section which may be cemented, glued, or otherwise suitably joined to the lower edge 16 of the dome 10. The annular rib 18 is preferably made of soft flexible material so that it will yield and thus distribute and transmit the weight of the dome to the shoulders without discomfort. Also the load of the dome is somewhat lightened by reason of the respiratory pressure exceeding that of the ambient air.

A seal 20 is in the shape of a collar having an inner diameter stretchable over the wearers head and is preferably made of relatively thin surgical sheet rubber, its outer diameter lying within the inner diameter of the annular rib 18, a portion at the extreme outer diameter of the seal being flanged upward as at 22 so as to lie alongside and be joined to the annular rib 18. The seal 20 is thicker at its outer diameter, tapering gradually to a very thin soft sheet at the inner diameter as at 24 ICC Y 2 whereby the pressure within the space 14 causes the thin sheet to fully conform to all the irregularities in the surface of the wearers neck. The upwardly flanged portion 22 is secured pressure tight to the inner side of the annular rib 18 by any suitable means depending on the nature of the material used in the rib. By reason of the seal being thicker at the outer diameter, the seal will not blow out when the dome is raised slightly from the shoulders by a considerable pressure difference between that in the space 14 and the ambient air.

Where the helmet is used with a partial pressure suit, the neck opening of the suit should underlap the seal for almost half the seal width as at 26. It is noted, however, that if the p.s.i. pressure in the space 14 is to be enough higher than that of the ambient air, provision must be made to arrest further upward movement of the dome. For this purpose straps 28 may be permanently attached to the dome at circumferentially spaced positions around the lower edge and fastened to the wearers suit with snap fasteners 30 or other similar devices. Any other means for limiting rise of the helmet beyond a predetermined amount will be considered within the scope of the invention. A sleeve 31 is provided for pressurizing the space 14.

In the modification shown in Fig. 2, a tapered seal 32 is flanged upwardly as at 34 and fastened by the flange to the outer diameter of the U-shaped annular rib 18. When the seal 32 is so placed the device is adapted for use where the p.s.i. within the helmet is less than that of the ambient air.

Fig. 2 shows the invention provided with both an inner seal 20 and an outer seal 32, whereby the device is adapted for use where the respiratory pressure is either greater or less than the pressure of the ambient air. It will be obvious, however, that the device may be furnished with the outer seal-32 only by omitting the inner seal 20 in situations where the ambient air pressure exceeds the leaving space between the hood and head, and the edge around the open end being shaped to approximately conform to the shoulder outline, an annular rib made of sponge rubber or similar soft material and made in U- shaped cross section being fitted over and secured to said edge, a seal in the form of a collar of highly flexible surgical sheet rubber the central opening of said collar being stretchable over the wearers head and flanged upwardly at the outer diameter to lie alongside the inner periphery of said sponge rubber rib and fastened pressure tight thereto, the thickness of said sheet rubber seal tapering from the outer upwardly flanged portion inwardly to a thin highly flexible portion around the centralopening, and means to receive fluid under pressure into the space between the dome, the wearers head, and the seal, whereby the thin inner edge of the seal collar is made by said pressure to conform to the irregularity of the neck surface of the wearer and thereby seal against pressure leakage from the space within the hood to the ambient air.

2. The device defined in claim 1 with a series of circumferentially spaced straps fastened to the dome near the lower open end thereof and extending downward past said lower end, with quick detachable means on the free ends of said straps for cooperation with quick detachable gesaou e 3. The device defined in claim 1 with an additional seal external of the hood which is in the form of a collar of highly flexible surgical sheet rubber flanged upwardly at the inner diameter to lie alongside the outer periphery of said sponge rubber rib and fastened pressure tight thereto, the thickness of said sheet rubber seal tapering from the inner upwardly flanged portion outwardly to a thin highly flexible portion around the outer periphery, where by the device is adapted to resist pressure leakage from the respiratory space to the ambient air or from the ambient air to the respiratory space.

4. A helmet comprising a dome-shaped hood of transparent material the lower open end of which is large enough to pass over the wearers head leaving space between the head and hood, and the edge around the open end being shaped to approximately conform to the shoulder outline, an annular rib made of soft material secured to said edge, a seal in the form of a collar of highly fiexible sheet material the central opening of said collar being passable over the wearers head and formed at the outer diameter to lie alongside the inner periphery of said annular rib and fastened pressure tight thereto, the thickness of said sheet rubber seal tapering from the outer portion inwardly to a thin highly flexible portion around the central opening, and means to receive fluid under pressure into the space between the dome, the wearers head, and the seal, whereby the thin inner edge of the seal collar is made by said pressure to conform to the irregularity of the neck surface of the wearer and thereby seal against pressure leakage from the respiratory space to the ambient air.

5. The device defined in claim 4 with means for connecting the dome to the suit of the wearer to limit rise of the dome from the wearers shoulders when the pressure in the dome exceeds that of the ambient air more than a predetermined amount.

6. A helmet comprising a dome-shaped hood of transparent material the lower open end of which is large enough to pass over the wearers head leaving space between the head and the hood, and the edge around the open end being shaped to approximately conform to the shoulder outline, a seal in the form of a collar of highly flexible sheet rubber or the like, the central opening of said collar being stretchable over the wearers head and the outer diameter adapted to lie near the inner periphery of said dome-shaped hood, the thickness of said sheet rubber seal tapering from the outer diameter inwardly to a thin highly flexible portion around the central opening, a second seal in the form of a collar of highly flexible sheet rubber or the like, the central opening being slightly larger than the dome at the lower open end, the thickness of the sheet rubber of said second collar tapering from the inner diameter outwardly to a thin highly flexible portion at the outer diameter, means for joining the outer diameter of the first seal and the inner diameter of the second seal pressure tight to the edge of the dome at the open end, and means to receive fluid under pres sure into the space between the dome, the wearers head, and the seal.

7. A helmet comprising a dome-shaped hood of transparent material the lower open end of which is large enough to pass over the wearers head leaving space between the head and hood, and the edge around the open end being shaped to approximately conform to the shoulder outline, an annular rib made of soft rubber or similar soft material and made in U shaped cross section fitted over and secured to said edge, a seal in the form of a collar of highly flexible sheet rubber or the like, the central opening of said collar being large enough to surround the outer periphery of said soft rubber rib and fastened pressure tight thereto, the thickness of said sheet rubber seal tapering from the inner diameter outwardly to a thin highly flexible portion at the outer diameter, and means to receive fluid under a pressure less than the ambient air pressure into the space between the dome and the wearers head, whereby the thin outer edge of the seal collar is made by said ambient air pressure to conform to the irregularity of the neck surface of the wearer and thereby seal against pressure leakage into said hood.

8. A helmet comprising a dome-shaped hood of transparent material, the lower open end of which is large enough to pass over the wearers head leaving space between the head and hood and the edge around the open end being shaped to approximately conform to the shoutder outline, a seal in the form of a collar of highly flexible sheet material, the central opening of said collar being large enough to be passed over the wearers head and the outer periphery of said collar lying close to the inner diameter of said open end, means for joining the outer periphery of said collar to the inner periphery of said open end pressure tight, the thickness of said sheet material tapering from the outer diameter inwardly to a thin highly flexible portion at the inner diameter, and means to receive a fluid under a pressure greater than the ambient air pressure into the space between the dome and the wearers head.

No references cited. 

